Continuous cleansing of rigid materials



ilhiiiliilil United States Patent 3,527,608 CONTINUOUS CLEANSING 0F RIGID MATERIALS Hans-Joachim Schliissler, Dusseldorf-Holthausen, Germany, assignor to Henkel 8r Cie., G.m.b.H., Dusseldorf'Holtllausellr Germany such as diethylenetriamines, triethylenetetramines and 'Y sg' c1965! 4 tetraethylenepentamines. The polyamines can be produced ms Pnomy app ca by the condensation of ethyleneimines and ammonia or Int. CL C238 1/14 1/18; 003a 23/00 ethmylenediamines. Furthermore, as nonionic wetting s CL 5 Claims 10 agents or detergents addition products of ethylene oxide and propylene oxide on alkylphenols may be used, preferably alkylphenols having an alkyl radical of 8 to 12 ABSTRACT OF THE DISCLOSURE carbon atoms; or addition products of ethylene oxide on fatty alcohols. An improvement 1n the continuous washing of rigid materials with a concentrated alkali washing bath which 15 r The .foam depressants wemng tgems or dam-gen? espectively, are present in the active concentrates in is periodically replenished comprising periodically reuant-t-es of 1 to 40 ht r t I f r b1 10 t 35 plenishing said washing bath in order to maintain a level q l 1 lg p6 Gen p e e a y o of from 0.02% to 0.4% of a stable liquid additive solui Percent tion comprisin fro t 407 b f Beside these wettmg agents or detergents and/or foa-m g m 0 o 0 y o a de ressants the active concentrates contain water-soluionic detergent, from 5% to 30% by weight of an organic h b] f 1 acid selected from the group of hydroxy and amino organic ac! S W 16 Fm capa o ormmg 09ml, ens with the hardness-forming constituents present in water. alkyl-Ll-diphosphonic acids, ethylenediaminotetra-(meth- I f th th Its b d Thi ylenephosphonic acid) and aminotri- (methylenephosphonn mu 0 ese elr acl e use s ic acid) an aliphatic alcohol and a mineral acid if ded-enotes Such salts which reaict acldlc m aqueous Solu- Sired i the balance Water tion and preferably those WhlCh have a pH of less than 3.5 in a 1% aqueous solution.

Especially suitable are organic phosphonic acids which form complexes with the hardness-formers in water and THE PRIOR ART have at least two phosphorus atoms in their molecules, For the cleansing of rigid materials, such as work such as hydroxyand aminoalkyl-l,l-diphosphonic acids pieces consisting of metal or glass, and especially for the having an alkyl radical of 2 to 6 carbons and aminomethcleansing of bottles, the use of alkaline materials is ylenephosphonic acids, particularly aminotri-(methyleneknown. These alkaline substances frequently contain, phosphonic acid) and ethylenediamino-tetra-(methyleneacid from caustic alkalies, soda, condensed phosphates phosphonic acid). such as pyro-, metaand polyphosphates, wetting agents The active concentrates according to the invention conand, as required, foam depressants (antifoams) and distain the water-soluble organic acids or their salts, respec-. infectants. In general, nonionic wetting agents or detertively, which are capable of forming complexes with the gents are used which exhibit pronounced antifoaming hardness formers found in water, in concentrations of 1 action, and, for binding of hardness-formers present in to weight percent, and preferably 5 to 30 weight perwater and for the prevention of scale or mineral forma- 40 cent. It is feasible to use mixtures of the acids named tion, polyphosphates. These products usually are sold in the concentrations as given. in commerce in form of powdered mixtures and are in- The active concentrates additionally may contain solucorporat'ed in the cleansing bath in batches, whereby the tion promoters, especially lower aliphatic alcohols having bath concentration of the cleaning agent usually lies be- 1 to 5 carbon atoms. The quantity of such promoters may tween 0.2 and 2 percent, depending upon the intended use be varied within a wide range and preferably is between 5 and degree of soilage. and 30 percent by weight. In most instances the addition In the past, liquid alkaline cleansing agent concentrates of such a solution promoter is not required for the produchave also been employed. However, upon prolonged stortion of homogeneous solutions. The active concentrate, in age of these alkaline concentrates, losses of polymeric addition, may contain mineral acids, e.g., phosphoric or phosphates occur due to hydrolysis. Moreover, nonionic Sulfuric acid, in cflllcentl'afions 0f Weight Percent-I wetting agents or detergents and antifoams and also poly- The remainder of the active concentrates always is water. phosphates cannot be incorporated in these concentrates The cleansing baths containing the active .,,concentrate in sufiicient quantities. are completed by the addition of an agent ccintaining an It now has been found that these drawbacks are avertalkali which is present in an excess. The term excess ed by the instant invention. The process for continuous n the CO C Of s inve tion is to denote a quantity of cleansing of rigid materials, especially glass bottles nd alkali-containing agents sufficient to neutralize not only metals, uses alkaline cleansers which are characterized the active concentrate but to impart to the mixture of the by a complement of a liquid, acid, active concentrate two components a pH above 11, and preferably above 12. containing a nonionic detergent and/or foam depressant, Opportunely the alkaline agent also is employed in the and also water-soluble organic acids which are capable 0 form of a concentrate of an aqueous component of prefof forming complexes with the hardness-causing ingredierably less than percent. In many instances, it is adents of water or acid salts of these acids, furthermore or vantageous to choose as the alkaline agent a concentrated agent containing alkali, the latter in an excess. alkali solution, e.g., sodiumor potassium hydroxide solu- Preferred nonionic wetting and antifoaming agents are tion. This constitutes the preferred embodiment of the inthose containing polyglycolether groups. These nonionic 5 vention. However, as desired or required, other alkaline wetting agents or detergents are obtained by the addition materials may be employed, such as alkali silicates, boof ethylene oxide on a hydrophobic component or by adrates or carbonates. dition of propylene oxide on a hydrophilic component. Furthermore, a portion of the complex formers may Advantagcously, addition products of ethylene oxide on be added to the alkaline agent. In general, however, it is polypropyleneglycol or on condensation products of pro- 7 preferred to incorporate the complex formers in the active pylene oxide and ethylene diamine are used. Other preferred nonionic wetting agents are addition products of "ice propylene oxide on polyalcohols, especially carbohydrates and polyglycerols, and particularly those having 2 to 10 glycerol groups per molecule; or else, addition prod; ucts of propylene oxide on short-chain alkanolamines, such as mono-, diand triethanolamine, or on polyamines concentrate because this enables, aside from other advantages, the use of two highly concentrated solutions.

The amounts of active concentrates to be put in the baths depend upon the water hardness and the material to be cleaned. Generally, the concentration of the active concentrates in the cleansing bath in 0.02 to 0.4 weight percent. When phosphonic acids having at least 2 phosphorus atoms in their molecules are present in the concentrate, it is added in such an amount that the quantity of these phosphonic acids in the entire bath is 100-300 mg./l.

The amount of alkaline agent simultaneously incorporated in the bath generally is 0.5 to 3.0 weight percent, preferably 1-2%, calculated on the total bath concentration.

The agents described are employed at the customary cleansing temperatures. In automatic bottle washing machines, these temperatures are approximately 60 to 80 C. When cleansing other n'gid materials, such as metals, the temperatures generally also are above 50 C.

The washing process according to the invention has the advantage that the active concentrate and the alkaline agent can be metered into the bath continuously. The active concentrate is completely stable even upon prolonged storage and insures good cleaning without foam formation and reliable prevention of scale formation in the washing devices.

The invention now will be further explained by the following examples. However, it should be understood that these are given merely by way of illustration, and not by limitation, and that numerous changes may be made in the details without departingfrom the spirit of the invention.

All percentages not particularly specified are weight percent. All solutions are aqueous.

Example 1 Weight parts Hydroxyethanediphosphonic acid Nonionic detergent (condensate of ethylene oxide with a reaction product of ethylene diamine and propylene oxide) 20 Water 60 Ethylenediaminotetra-(methylene phosphonic acid) 20 Nonionic detergent (same as in (a)) 20 Water 60 The results obtained, i.e., the layers formed on the sheet metal, are compiled in Table 1.

TABLE l.LAYER FORMED (gJmJ) Water hardness l Additive (In addition to 1% NaOH) Test No.

OI aoom awwaqu 1 The hardness degrees used in all examples are d.H.." l.e., German standard hardness degrees, wherein 1d.H.=10 mg. CaO/l.

4 Example 2 Beer bottles were cleaned in a commercial bottle washing machine having 2 solution zones and an hourly throughput of 16,000 bottles. As cleansing solution a 1% aqueous NaOH solution was used in each zone which had been produced by dilution of 50% NaOH. To this solution, 0.075 weight percent of an active concentrate were added consisting of 25% hydroxyethanediphosphonic acid, 35% nonionic detergent (condensation product of ethylene oxide with polypropyleneglycol), 10% ethanol, and the remainder water. The water used for cleansing had a temporary hardness of approximately 36. The cleansing solution was applied at a temperature of 70 C. and was kept at the original strength by means of addition of 50% NaOH and active concentrate, as required.

The bottles were entirely clean, and the labels had come off. No foam formation occurred during the 6-day use of the wash.

Example 3 The water available had a temporary hardness of 25 The temperature of the cleansing solution was 70-75 C. The mineral water bottles emerged from the process well cleaned, and undisturbed refilling of the bottles was observed.

Example 4 Milk bottles were cleaned in a commercial bottle washing machine having two solution zones and a throughput of 12,000 units per hour. The cleansing solution for each zone was a 1.2 weight percent potassium hydroxide solution. To this solution, 0.15 weight percent of an active concentrate were added having the following composition:

Percent weight 'Monopotassiumhydroxyethanediphosphonate 10 Nonionic detergent, as in Example 1 (a) 10 Water The cleansing solution was made up to its original strength, as required, by addition of KOH and active concentrate. The water used had a temporary hardness of 8, the temperature of the cleansing solution was 65 C.

The bottles were entirely clean after washing, scale formation was successfully prevented, and no foaming occurred in the cleansing bath.

Like results were obtained by using as nonionic detergents addition products of ethylene oxide on polypropylene; addition products of propylene oxide on carbohydrates or on polyglycerols having 2 to 10 glycerol groups per molecule; addition products of propylene oxide on short-chain alkanolamines, e.g., mono-, diand triethanolamine; addition products of propylene oxide on polyamines produced by condensation of ethyleneimine with ammonia or ethylenediamine; addition products of ethylene oxide on fatty alcohols, preferably C to C alcohols; or addition products of ethylene oxide and propylene oxide on alkylphenols having an alkyl of 8-12 carbon atoms.

Example 5 Soft drink bottles were cleaned in a commercial bottle washing machine equipped with 3 dip-washing zones. For the several zones, a 2% aqueous NaOH was used. To

this solution, 0.1 weight percent of an active concentrate were added consisting of 20% by weight aminoethanediphosphonic acid, 30% nonionic detergent (a condensation product of ethylene oxide with polypropyleneglycol), ethanol and the balance water. The original strength of the baths was kept up by the addition of NaOH and active concentrate, as required. The water employed had a temporary hardness of 16, and the cleansing solution was at a temperature of 80 C. The bottles were well cleaned after passing the machine, no foam was observed and no scale formation in the warm water zone, even after prolonged activity.

Example 6 The baths, as required, were replenished by addition of NaOH and active concentrate. The bath temperature was approximately 70 C., and the wash water had a temporary hardness of approximately 17. The cleansing action was excellent, and even after prolonged use of the solution, no foaming nor scale formation could be observed.

Example 7 Wine bottles were cleaned in a small automatic washer having an hourly throughput of 4,000 bottles at a temperature of 70 C. The cleansing solution was a 1.5% NaOH to which 0.15 percent of an active concentrate had been added consisting of the following:

Percent weight Hydroxypentanediphosphonic acid Nonionic detergent (addition product of 27.5 mols propylene oxide on triethanolamine) 20 Water 60 The water employed had a temporary hardness of 12. The solution was brought up to strength, as required, by addition of 50% NaOH and active concentrate.

The cleansing effect was excellent even in instances of strong soilage by residual red wine. No scale formation occurred in the warm water zone, and no foaming took place in the solution zone, during the duration of the test which lasted several days.

Example 8 Dirty motor parts were cleaned in a dual chamber spray washing device with a 1.5% aqueous NaOH solution at 70 C. To the solution, 0.1 percent of an active concentrate were added having the following composition:

Percent weight Aminobutanediphosphonic acid 30 Nonionic detergent as in Example 1 (a) Addition product of 9 mols ethylene oxide and 10 mols propylene on nonylphenol 1 Water 44 The water used had a temporary hardness of 20. The motor parts could be sprayed clean with this solution.

Example 9 Beer bottles were cleaned in a commercial bottle washing machine having two solution zones. In both these zones a cleansing solution was employed containing 1% NaOH and 0.1% of an active concentrate composed as follows:

Percent weight Aminotri-(methylenephosphonic acid) 25 Nonionic detergent (condensation product of ethylene oxide with propylene glycol) 25 Water 50 The water used had a temporary hardness of 15. The

Nonionic detergent as in Example 1 20 Addition product of 9 mols ethylene oxide and 10 mols propylene oxide on nonylphenol 1 Isopropanol 10 Water 49 Example 10 Soft drink bottles were cleaned in a commercial bottle washing machine having three dip zones. For the several dipping baths, a 1.2% aqueous NaOH was used to which 0.15% of an active concentrate were added having the following composition:

Percent weight Ethylenediaminotetra-(methylenephosphonic acid) 20 Nonionic detergent (condensation product of ethylene oxide with propyleneglycol) 20 Ethanol 15 Water 45 The solution was used at a temperature of 70-80 C. and replenished by addition of active concentrate and NaOH when required. The water had a temporary hardness of 6. Cleansing action was very good, no foam developed, and so scale formation took place even upon prolonged use.

Like results were obtained when as the active concentrate 0.25% of the following mixture were employed, in lieu of the one given above:

Percent weight Monosodium salt of ethylenediaminotetra-(methylenephosphonic acid) 10 Nonionic detergent as in Example 1 10 Water Example 11 Beer bottles were cleaned in a commercial bottle washing machine having two cleansing zones. In both these zones, a cleansing solution was employed which contained 1% NaOH and to which had been added 0.1% of an active concentrate of the following composition:

Percent weight Hydroxyethanediphosphonic acid 20 Nonionic detergent (addition product of 5 mols propylene oxide per N-atom on tetraethylenepentamine) Water The water used had a temporary hardness of 15 The cleansing solutions were applied at a temperature of 60- 65 C. and replenished as required by addition of NaOH and active concentrate. Cleansing action and removal of the labels were faultless. Calcification in the warm water zone could not be observed, and no foam developed during the time of application.

Example 12 Milk bottles were cleansed in a commercial bottle washing machine having two wash zones and an hourly capacity of 10,000 units. The solutions for both zones had 2.5% NaOH and 0.12% of an active concentrate of the following composition:

Percent weight Aminotri-(methylphosphonic acid) 20 Nonionic detergent (additive of 9 mols ethylene oxide and 10 mols propylene oxide on nonylphenol) 20 Isopropanol 15 Phosphoric acid (75%) 20 Water 25 Aminotri-(methylenephosphonic acid) 20 Nonionic detergent (additive of 2 ethylene oxide) groups on oleyl alcohol) 20 Isopropanol 25 Sulfuric acid (96%) 15 Water 20 I claim as my invention:

1. In the continuous process for cleaning rigid materials which comprises continuously passing said rigid materials through a periodically replenished washing bath having a pH of about 11 and a temperature above 50' C., and a rinsing bath, said washing bath being composed essentially of from 0.5% to 3% by weight of an alkali selected from the group consisting of sodium hydroxide .and potassium hydroxide and from 0.02% to 0.4% of a liquid additive containing a non-ionic detergent, the balance being water and periodically replenishing said alkali and said liquid additive as the same is consumed, the improvement which consists of utilizing as said liquid additive being periodically replenished, a stable aqueous acid active concentrate solution composed of from 1% to 40% by weight of a non-ionic detergent and from 5% to 30% by weight of an organic water-soluble acid selected from 8 the group consisting of hydroxy and amino alkyl-1,1-diphosphonic acids having an alkyl of from 2 to 6 carbon atoms, ethylenediaminotetia(methylenephosphonic acid) and aminotri-(methylenephosphonic acid), said active concentrate having a pH of below 3.5 in a 1% aqueous solution.

2. The process of claim 1 wherein said washing bath being periodically replenished is maintained at a concentration of said organic water-soluble acid of from mg./1. to 300 mgJl.

3. The process of claim 1 wherein said active concentrate also contains 5 to 30 weight percent of an aliphitac alcohol having 1 to 5 carbon atoms and a proportionately lower water content.

4. The process of claim 1 wherein said active concentrate, in addition to the ingredients named, contains 1 to 30 weight percent of a mineral acid.

5. The process of claim 4 wherein said mineral acid is selected from the group consisting of sulfuric and phosphoric acid.

References Cited UNITED STATES PATENTS 2,599,807 6/1952 Bersworth. 2,615,846 10/1952 Dvorkovitz et al. 252--156 2,976,248 3/1961 Otrhalek 252156 2,991,244 7/1961 Pattenden 252-33.2 3,288,846 11/1966 Irani et al. 3,367,878 2/ 1968 Mankowich 252-138 XR FOREIGN PATENTS 571,529 3/ 1959 Canada. 790,160 2/ 8 Great Britain.

OTHER REFERENCES Surfactants That Improve Alkaline Bottle Washing, Antara Chemicals, 1959 (p. 3 relied on).

Detergents and Emulsifies (1963 Annual), John Mc- Cutcheon, Inc. (pp. 74 and 77 relied on).

MORRIS O. WOLK, Primary Examiner B. S. RICHMAN, Assistant Examiner US. Cl. X.R. 

